OBJECTIVE: To provide a reliable data base for comparison of pathological gait with normal gait in children. This is a cross sectional study of the walking patterns of normal children from the onset of independent walking through seven years of age. A Vanguard motion analyzer, sonic digitizer, computer and plotter facilitate the recording of the multiple measurements required and the plotting of the curves. In addition, floor reaction forces are measured by a force plate and external joint torques are calculated. Femoral antetorsion and neck shaft angles are determined by a technique utilizing fluoroscopy with image intensifier, 70 mm camera and Vanguard motion analyzer. Angular rotations, linear measurements and ground reaction forces are used to define evolving gait pattersn. Surface electromyograms provide information on the phasic activity of muscle groups. We seek to identify gait parameters which are the best indicators of mature gait. A specific goal is to establish a firm data to compare pathological gait patterns with reliable normal controls at each age through seven years.